Multi-cyclone dust collection device and vacuum cleaner comprising same

ABSTRACT

A multi-cyclone dust collector and a vacuum cleaner having the same are provided. The multi-cyclone dust collector includes a primary cyclone separator provided to separate waste primarily from introduced waste-containing air, and a secondary cyclone separator installed inside the primary cyclone separator to separate dust from air discharged from the primary cyclone separator. The secondary cyclone separator includes a secondary cyclone provided with two inlet holes through which air is introduced and an outlet hole through which the introduced air is discharged, and an upper cover provided to cover an upper end of the secondary cyclone and including an outlet pipe inserted into the outlet hole to discharge the air. The upper cover further includes a plurality of flow guides disposed between adjacent inlet holes to minimize airflow interference between the adjacent inlet holes and provided on an outer surface of the outlet pipe to correspond to the at least two inlet holes.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application, claiming priority under § 365(c), of an International application No. PCT/KR2022/004370, filed on Mar. 29, 2022, which is based on and claims the benefit of a Korean patent application number 10-2021-0050419, filed on Apr. 19, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to a cyclone dust collector of a cleaner. More particularly, the disclosure relates to a multi-cyclone dust collector including a primary cyclone and a secondary cyclone and a vacuum cleaner having the same.

2. Description of Related Art

Instead of a wired vacuum cleaner supplied with electricity by connecting a wire to an external power source, a cordless vacuum cleaner operating using electricity output from a built-in battery without a wire connected to an external power source is widely used.

A multi-cyclone dust collector using a centrifugal force is used as a dust collector for collecting dust and waste in such a cordless vacuum cleaner.

The multi-cyclone dust collector includes a primary cyclone to separate and collect waste and dust from air containing waste introduced from the outside, and a plurality of secondary cyclones to separate fine dust from the air discharged from the primary cyclone.

In the case of the secondary cyclone, a pressure loss may occur due to a pressure difference between air entering an inlet hole and air exiting an outlet hole.

As a pressure loss of a multi-cyclone dust collector increases, a suction force of a vacuum cleaner itself, that is, cleaning performance is reduced, and thus the pressure loss needs to be minimized.

The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide a multi-cyclone dust collector capable of minimizing a pressure loss and airflow loss in a secondary cyclone and a vacuum cleaner having the same.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a multi-cyclone dust collector is provided. The multi-cyclone dust collector includes a primary cyclone separator provided to separate waste primarily from introduced waste-containing air, and a secondary cyclone separator installed inside the primary cyclone separator to separate dust from air discharged from the primary cyclone separator, wherein the secondary cyclone separator includes a secondary cyclone provided with at least two inlet holes through which air is introduced and an outlet hole through which the introduced air is discharged, and an upper cover provided to cover an upper end of the secondary cyclone and including an outlet pipe inserted into the outlet hole to discharge the air, and wherein the upper cover further includes a plurality of flow guides disposed between adjacent inlet holes to minimize airflow interference between the adjacent inlet holes and provided on an outer surface of the outlet pipe to correspond to the at least two inlet holes.

The at least two inlet holes may be provided at an upper end of an outer circumferential surface of a body of the secondary cyclone to protrude outward from the body, and the plurality of flow guides may be provided at positions higher than a lower end of the outlet pipe to correspond to the at least two inlet holes.

Each of the plurality of flow guides includes a guide surface extending toward the lower end of the outlet pipe to guide air introduced into each of the at least two inlet holes to be moved to the lower end of the outlet pipe.

The at least two inlet holes may be formed in a tangential direction with respect to an outer circumferential surface of each of the secondary cyclones, and one of the plurality of flow guides includes a guide surface provided to guide air introduced into one of the at least two inlet holes.

Each of the at least two inlet holes includes an opening formed on each of the bodies of the secondary cyclones, and an inlet duct formed to surround the opening to allow air to flow in a tangential direction with respect to an outer circumferential surface of the body, and the guide surface may be provided to face the opening of the corresponding inlet hole.

The guide surface may extend downward from one end thereof to the other end and be formed to be away from the corresponding inlet hole from the one end toward the other end.

The guide surface may have a spiral shape along a circumference of the outlet pipe.

The guide surface may be provided to be inclined with respect to the tangential direction.

The one flow guide includes a blocking surface provided on a side opposite to the guide surface facing the one inlet hole to block air introduced from an inlet hole adjacent to the one inlet hole from being moved toward the one inlet hole.

The blocking surface may extend from one end thereof to the other end in a direction parallel to an extending direction of the outlet pipe.

The other end of the guide surface and the other end of the blocking surface may be in contact with each other.

The flow guide further includes a cover surface provided to cover a space between the guide surface and the blocking surface, and the guide surface, the blocking surface and the cover surface may be integrally formed.

A plurality of the secondary cyclones may be provided, and the upper cover may be provided to cover upper portions of the plurality of secondary cyclones and including a plurality of the outlet pipes corresponding to the plurality of secondary cyclones.

The plurality of secondary cyclones includes a central cyclone provided to correspond to a center of the upper cover and eight peripheral cyclones provided to correspond to a circumference of the upper cover, and the first cyclone may have four inlet holes and each of the second cyclones may have three inlet holes.

In accordance with another aspect of the disclosure, a vacuum cleaner is provided. The vacuum cleaner includes a suction nozzle, a multi-cyclone dust collector connected to the suction nozzle, and a suction motor connected to the multi-cyclone dust collector and provided to generate a suction force, wherein the multi-cyclone dust collector includes a primary cyclone separator provided to separate waste primarily from introduced waste-containing air, and a secondary cyclone separator installed inside the primary cyclone separator to separate dust from air discharged from the primary cyclone separator, wherein the secondary cyclone separator includes a secondary cyclone provided with at least two inlet holes through which air is introduced and an outlet hole through which the introduced air is discharged, and an upper cover provided to cover an upper end of the secondary cyclone and including an outlet pipe inserted into the outlet hole to discharge the air, and wherein the upper cover further includes a plurality of flow guides disposed between adjacent inlet holes to minimize airflow interference between the adjacent inlet holes and provided on an outer surface of the outlet pipe to correspond to the at least two inlet holes.

The at least two inlet holes may be formed in a tangential direction with respect to an outer circumferential surface of each of the secondary cyclones, and one of the plurality of flow guides includes a guide surface provided to guide air introduced into one of the at least two inlet holes.

The guide surface may extend downward from one end thereof to the other end and be formed to be away from the corresponding inlet hole from the one end toward the other end, and have a spiral shape along a circumference of the outlet pipe.

The body includes a hollow cylindrical part provided with the at least two inlet holes and a hollow truncated conical part provided at a lower end of the hollow cylindrical part, the cylindrical part and the truncated conical part may be integrally formed, and the upper cover may be formed separately from the cylindrical part.

According to an embodiment of the disclosure, a collection efficiency of a multi-cyclone dust collector can be improved by minimizing a pressure loss and airflow loss in a secondary cyclone.

Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a multi-cyclone dust collector according to an embodiment of the disclosure;

FIG. 2 is a cross-sectional view taken by cutting the multi-cyclone dust collector along line II-II′ in FIG. 1 according to an embodiment of the disclosure;

FIG. 3 is a cross-sectional view taken by cutting the multi-cyclone dust collector along line III-III′ in FIG. 2 according to an embodiment of the disclosure;

FIG. 4 is a perspective view illustrating a secondary cyclone of the multi-cyclone dust collector according to an embodiment of the disclosure;

FIG. 5 is a longitudinal cross-sectional view of the secondary cyclone in FIG. 4 according to an embodiment of the disclosure;

FIG. 6 is an exploded perspective view illustrating a state in which an integral body of a plurality of secondary cyclones and an upper cover of the multi-cyclone dust collector are separated according to an embodiment of the disclosure;

FIG. 7 is a view illustrating the secondary cyclone in FIG. 6 according to an embodiment of the disclosure;

FIG. 8 is a view illustrating the secondary cyclone illustrated in FIG. 7 from another side according to an embodiment of the disclosure;

FIG. 9 is a view illustrating another example of a secondary cyclone of a multi-cyclone dust collector according to an embodiment of the disclosure;

FIG. 10 is a view illustrating a vacuum cleaner equipped with a multi-cyclone dust collector according to an embodiment of the disclosure; and

FIG. 11 is a partial cross-sectional view illustrating the multi-cyclone dust collector installed in the vacuum cleaner in FIG. 10 according to an embodiment of the disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.

Like reference numbers or signs in the various drawings of the application represent parts or components that perform substantially the same functions.

The terms used herein are for the purpose of describing the embodiments and are not intended to restrict and/or to limit the disclosure. Also, the terms “comprises” and “has” are intended to indicate that there are features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not exclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

It will be understood that, although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms, and the terms are only used to distinguish one component from another. For example, without departing from the scope of the disclosure, the first component is referred to as a second component, and similarly, the second component may also be referred to as a first component. The term “and/or” includes any combination of a plurality of related items or any one of a plurality of related items.

Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a multi-cyclone dust collector according to an embodiment of the disclosure.

FIG. 2 is a cross-sectional view taken by cutting the multi-cyclone dust collector along line II-II′ in FIG. 1 according to an embodiment of the disclosure.

FIG. 3 is a cross-sectional view taken by cutting the multi-cyclone dust collector along line III-III′ in FIG. 2 according to an embodiment of the disclosure.

Referring to FIGS. 1 to 3 , a multi-cyclone dust collector 1 according to an embodiment of the disclosure may include a primary cyclone separator 10 and a secondary cyclone separator 20.

The primary cyclone separator 10 is configured to primarily separate large-sized waste and dust by swirling air containing introduced waste using a centrifugal force acting on the air containing the waste. The air from which waste and dust are primarily separated in the primary cyclone separator 10 is discharged to the secondary cyclone separator 20.

The primary cyclone separator 10 may be implemented by a housing 11 forming an outer appearance of the multi-cyclone dust collector 1 and an intermediate wall 12 installed inside the housing 11.

The housing 11 is formed in a substantially hollow cylindrical shape and includes a bottom 11 a formed at one end. That is, the housing 11 is formed in the shape of a cylindrical container with the bottom 11 a. An inlet port 11 b is provided on an outer circumferential surface of the housing 11, that is, on an upper portion of a side wall, through which air containing external waste is introduced. The inlet port 11 b of the housing 11 may communicate with a suction nozzle 170 (see FIG. 10 ) of a vacuum cleaner 100 through an extension pipe 160 (see FIGS. 10 and 11 ). Therefore, waste and dust on a surface to be cleaned that are sucked through the suction nozzle 170 are drawn into the primary cyclone separator 10 through the inlet port 11 b.

The intermediate wall 12 is formed in a hollow cylindrical shape to be installed inside the housing 11 concentrically with the housing 11. Because the intermediate wall 12 is spaced apart from the side wall of the housing 11 by a predetermined distance, a donut-shaped space is formed between the intermediate wall 12 and the housing 11. The air containing waste drawn into the inlet port 11 b of the housing 11 is swirled in a space between the intermediate wall 12 and the side wall of the housing 11. The waste and dust separated by the centrifugal force in the primary cyclone separator 10 are collected on the bottom 11 a of the housing 11.

The intermediate wall 12 may include a porous member 13. The porous member 13 may be provided along an entire circumference of the intermediate wall 12 at a substantially intermediate portion in a longitudinal direction of the intermediate wall 12. The porous member 13 may be formed in a shape having a plurality of holes, such as a grill and filter, to allow air to pass through and not to pass large-sized waste and dust. The porous member 13 functions as an outlet hole through which air from which waste and dust are primarily removed in the primary cyclone separator 10 is discharged. Accordingly, an inner space of the intermediate wall 12 may form an intermediate chamber 17 in which air discharged from the primary cyclone separator 10 through the porous member 13 is collected.

The secondary cyclone separator 20 is installed inside the intermediate wall 12, that is, in the intermediate chamber 17. Therefore, the intermediate wall 12 partitions the secondary cyclone separator 20 and the primary cyclone separator 10.

The secondary cyclone separator is formed to separate fine dust from the air discharged from the primary cyclone separator 10. The air discharged from the primary cyclone separator 10 is in a state in which large-sized waste and dust are removed and only fine dust is contained.

The secondary cyclone separator 20 includes a secondary cyclone 20′ and an upper cover 14 covering an upper end of the secondary cyclone 20′.

The secondary cyclone 20′ may include a plurality of inlet holes 30 and one outlet hole 25.

The plurality of inlet holes 30 is formed to protrude outward from an outer circumferential surface of the secondary cyclone 20′ and is open toward the intermediate chamber 17. Specifically, each of the plurality of inlet holes 30 is formed to protrude outward from an outer circumferential surface of a body 21 of the secondary cyclone 20′. In addition, each of the plurality of inlet holes 30 is formed in a tangential direction with respect to the secondary cyclone 20′. That is, each of the inlet holes 30 is formed to protrude outward in a tangential direction with respect to the outer circumferential surface of the body 21 of the secondary cyclone 20′. Thus, the air in the intermediate chamber 17 is introduced into the secondary cyclone 20′ in the tangential direction.

The outlet hole 25 is formed at the upper end of the secondary cyclone 20′. Specifically, the outlet hole 25 is formed at a center of an upper end of the body 21 of the secondary cyclone 20′.

A lower plate 15 blocking a lower portion of the intermediate wall 12 is installed at a lower end of the secondary cyclone 20′. That is, the lower plate 15 is installed inside the intermediate wall 12 to partition a dust collection chamber 40 provided below the secondary cyclone 20′ and the intermediate chamber 17 in which the secondary cyclone 20′ is installed. A hole into which the lower end of the secondary cyclone 20′ may be inserted is formed on the lower plate 15.

The dust collection chamber 40 is formed below the secondary cyclone 20′ to collect fine dust separated from the secondary cyclone 20′. The dust collection chamber 40 may be formed by a dust collection container 41 extending upward in a substantially funnel shape from a central portion of the bottom 11 a of the housing 11. The dust collection container 41 may be surrounded by the intermediate wall 12 extending downward by a predetermined length beyond the lower plate 15.

A space around an outer circumference of the dust collection container 41 of the bottom 11 a of the housing 11 forms a waste collection chamber 44 in which waste separated by the primary cyclone separator 10 is collected. The dust collection chamber 40 is shielded with a dust collection container 41 so as not to communicate with the waste collection chamber 44.

The upper cover 14 covering the upper end of the secondary cyclone 20′ is provided to block an upper portion of the intermediate wall 12. The upper cover 14 blocks the upper end of the body 21 of the secondary cyclone 20′ so that the intermediate chamber 17 in which the secondary cyclone 20′ is installed does not communicate with the outside. Accordingly, a space surrounded by the intermediate wall 12, the upper cover 14, and the lower plate 15 forms the intermediate chamber 17 in which the body 21 of the secondary cyclone 20′ is disposed.

The upper cover 14 may include an upper plate 14 a, an outlet pipe 25 a, and a plurality of flow guides 70. The plurality of flow guides 70 will be described later.

The upper plate 14 a is positioned inside the primary cyclone separator 10 and thus may be provided in a disk shape, but is not limited thereto and may be provided in various shapes.

The outlet pipe 25 a may be provided to correspond to the secondary cyclone 20′. The outlet pipe 25 a may extend downward from the upper plate 14 a. The outlet pipe 25 a may be formed in a circular pipe shape. Therefore, when the upper cover 14 covers the upper end of the secondary cyclone 20′, as illustrated in FIG. 2 , the outlet pipe is inserted into the outlet hole of the secondary cyclone 20′ so that the outlet pipe is positioned at the upper end of the secondary cyclone 20′. Therefore, the air introduced into the intermediate chamber 17 is introduced into the inlet holes 30 of the plurality of secondary cyclones 20′, swirled inside the secondary cyclones 20′, and discharged to the outside through the outlet pipe 25 a.

A base 50 is provided above the secondary cyclone 20′, which functions as a passage for air discharged from the secondary cyclone 20′ and which may fix the multi-cyclone dust collector 1 to the vacuum cleaner. The base 50 communicates with a suction motor generating a suction force. The multi-cyclone dust collector 1 according to this embodiment may be installed in the cordless vacuum cleaner 100 as illustrated in FIG. 11 .

The base 50 is formed in a substantially hollow cylindrical shape, the upper cover 14 is installed at a lower end of the base 50, and an upper end of the base 50 is open. Accordingly, the air discharged from the outlet pipe 25 a of the secondary cyclone 20′ passes through the inside of the base 50 and is discharged to the upper end of the base 50.

The intermediate wall 12 described above is formed to extend from the lower end of the base 50. The housing 11 may be detachably installed at an upper portion of the base 50 to the outside of the intermediate wall 12.

One or more of the secondary cyclones 20′ may be provided, and in this case, the upper cover 14 may be provided to cover upper portions of the secondary cyclones 20′.

Referring to FIG. 3 , a plurality of the secondary cyclones 20′ may be provided, and nine of the secondary cyclones 20′ may be provided to be arranged in a circular shape. Specifically, one of the secondary cyclones (central cyclone 20′c) may be arranged in a center, and eight of the secondary cyclones (peripheral cyclones 20′d) may be arranged in a circular shape around the central cyclone 20′c (see FIG. 6 ). This structure may be applied when the multi-cyclone dust collector 1 according to an embodiment of the disclosure is used in the vacuum cleaner 100 as illustrated in FIG. 10 .

However, the number and arrangement of the secondary cyclones 20′ as described above is only an example, and the secondary cyclones 20′ is arranged in various numbers and in various forms depending on cordless vacuum cleaners to which the multi-cyclone dust collector 1 are applied.

Hereinafter, each of the secondary cyclones of the multi-cyclone dust collector according to an embodiment of the disclosure will be described in detail with reference to FIGS. 4 and 5 .

FIG. 4 is a perspective view illustrating a secondary cyclone of the multi-cyclone dust collector according to an embodiment of the disclosure.

FIG. 5 is a longitudinal cross-sectional view of the secondary cyclone in FIG. 4 according to an embodiment of the disclosure.

FIG. 6 is an exploded perspective view illustrating a state in which an integral body of a plurality of secondary cyclones and an upper cover of the multi-cyclone dust collector are separated according to an embodiment of the disclosure.

Referring to FIGS. 4 to 6 , each of the plurality of secondary cyclones 20′ according to an embodiment of the disclosure may include a cylindrical part 22 and a truncated conical part 23, and the upper end thereof may be covered by an upper plate 24, which is a portion of the upper cover 14.

The cylindrical part 22 is formed in a hollow cylindrical shape, and the plurality of inlet holes 30 is provided on an outer circumferential surface of the cylindrical part 22. The plurality of inlet holes 30 is formed to protrude outward from an outer circumferential surface of the cylindrical part 22 of the secondary cyclone 20′. Each of the plurality of inlet holes 30 is formed in a tangential direction with respect to the outer circumferential surface of the cylindrical part 22 of the secondary cyclone 20′. That is, each of the plurality of inlet holes 30 protrudes outward from the outer circumferential surface of the cylindrical part 22 of the secondary cyclone 20′ and is formed in the tangential direction with respect to the outer circumferential surface of the cylindrical part 22.

The plurality of inlet holes 30 is formed to be in contact with the outer circumferential surface of the cylindrical part 22 having a maximum diameter. As such, the plurality of inlet holes 30 is formed on the outer circumferential surface of the cylindrical part 22 having the maximum diameter of the secondary cyclone 20′, a separation efficiency may be maintained. In addition, when the plurality of inlet holes 30 is formed in the secondary cyclone 20′, a pressure loss generated in the secondary cyclone 20′ may be reduced compared to a conventional secondary cyclone having one inlet hole. In addition, when the plurality of inlet holes 30 is formed to protrude from the outer circumferential surface of the secondary cyclone 20′, an air flow path is formed such that the air in the intermediate chamber 17 may be smoothly introduced into the secondary cyclone 20′ through the plurality of inlet holes 30. In addition, because the plurality of inlet holes 30 is formed in the tangential direction on the outer circumferential surface of the secondary cyclone 20′, air is introduced into the secondary cyclone 20′ in the tangential direction through the plurality of inlet holes 30, so that a centrifugal force acting on the air being swirled inside the secondary cyclone 20′ may be maximized.

The truncated conical part 23 is provided at a lower end of the cylindrical part 22 and is formed in a hollow shape. A lower end of the truncated conical part 23 is open to form a dust outlet 26 through which the separated dust is discharged. The truncated conical part 23 is integrally formed with the cylindrical part 22 to form the body 21 of the secondary cyclone 20′.

The upper plate 24 is installed at an upper end of the cylindrical part 22, and has the outlet hole 25 through which air introduced into the secondary cyclone 20′ is discharged through the plurality of inlet holes 30.

The upper plate 24 may be formed to block the upper end of the cylindrical part 22. The shape of the upper plate 24, which is a part of the upper cover 14, may be variously changed.

The outlet hole 25 may be installed in a center of the upper plate 24. The outlet hole 25 may be formed with outlet pipe 25 a having a circular pipe shape of a certain length.

The upper plate 24 may be formed separately from the cylindrical part 22 to facilitate molding of the secondary cyclone 20′. The cylindrical part 22 including the plurality of inlet holes 30 may be integrally formed with the truncated conical part 23. That is, the secondary cyclone 20′ may be formed by molding the upper plate 24 including the outlet hole 25 separately from the body 21 composed of the truncated conical part 23 and the cylindrical part 22.

Referring to FIG. 6 , the plurality of inlet holes 30 is provided at regular intervals on the outer circumferential surface of the cylindrical part 22 of the secondary cyclone 20′. In this embodiment, three of the inlet holes 30 are provided on the secondary cyclone 20′, but this is only an example, and two of the inlet holes 30 may be formed, or four or more of the inlet holes 30 may be formed.

The plurality of inlet holes 30 may include a plurality of openings 35 formed on the outer circumferential surface of the secondary cyclone 20′, and a plurality of inflow ducts 31 formed to protrude from the outer circumferential surface of the secondary cyclone 20′ and surround the plurality of openings 35. That is, each of the inlet holes 30 of the secondary cyclone 20′ may include the opening 35 formed at the upper end of the outer circumferential surface of the cylindrical part 22 and the inflow duct 31 surrounding the opening 35.

The inflow duct 31 is formed in a substantially triangular columnar shape, and is formed to introduce air in the tangential direction with respect to the outer circumferential surface of the secondary cyclone 20′. Specifically, as illustrated in FIG. 4 , the inflow duct 31 may include an inflow guide wall 32 installed in the tangential direction with respect to the body 21 of the secondary cyclone 20′, and a lower wall 34 connecting a lower end of the inflow guide wall 32 and the outer circumferential surface of the body 21 of the secondary cyclone 20′.

An upper end of the inflow guide wall 32 may be connected to the upper plate 24. Therefore, an inlet of the inflow duct 31 formed by the upper plate 24, the inflow guide wall 32, and the lower wall 34 is formed in a substantially rectangular shape.

The inflow guide wall 32 is formed in a substantially rectangular flat plate and is installed in the tangential direction with respect to the cylindrical part 22 of the secondary cyclone 20′. That is, the inflow guide wall 32 is installed in the tangential direction at one end of the opening 35 of the cylindrical part 22 of the secondary cyclone 20′.

The lower wall 34 is formed in a substantially triangular flat plate and connects the lower end of the inflow guide wall 32 and a side surface of the cylindrical part 22 of the secondary cyclone 20′. Accordingly, a side of the lower wall 34 in contact with the side surface of the cylindrical part 22 may be formed in an arc shape corresponding to the cylindrical part 22 of the secondary cyclone 20′. The lower wall 34 forms a lower end of the inlet hole 30. Therefore, the lower wall 34 may be installed at the same or higher position as a lower end 25 b of the outlet pipe 25 a forming the outlet hole 25.

When the multi-cyclone dust collector 1 according to another embodiment of the disclosure is used in the cordless vacuum cleaner 100 illustrated in FIG. 11 , it is necessary to increase a suction force while a size of the multi-cyclone dust collector 1 is as small as possible.

Referring to FIG. 3 , nine of the secondary cyclones 20′ may be arranged. In this case, it is appropriate that three of the inlet holes 30 are formed on the secondary cyclone 20′. The secondary cyclone 20′ may be formed to have two or four or more of the inlet holes 30, but a larger pressure loss may occur than when the secondary cyclone 20′ has three of the inlet holes 30. Therefore, the multi-cyclone dust collector 1 used in the cordless vacuum cleaner having the size limitation as in the embodiment is preferably formed such that each of the plurality of secondary cyclones 20′ has three of the inlet holes 30.

However, it is appropriate that the central cyclone 20′c corresponding to a center of the upper cover 14 of the secondary cyclone separator 20 has four of the inlet holes. Considering that each of the eight peripheral cyclones 20′d arranged to correspond along a circumference of the upper cover 14 to the periphery of the central cyclone 20′c has the three inlet holes 30, the central cyclone 20′c may more smoothly flow air when having the four inlet holes 30.

When the plurality of secondary cyclones 20′ is provided as described above, the upper plate 24, which is a part of the upper cover 14 corresponding to the upper end of each of the plurality of secondary cyclones 20′, may form the upper cover 14 covering upper ends of the plurality of secondary cyclones 20′.

On the other hand, when one of the secondary cyclone 20′ is provided, the upper plate 24 corresponding to the upper end of the one secondary cyclone 20′ may be the upper cover 14 described above.

FIG. 7 is a view illustrating the secondary cyclone in FIG. 6 according to an embodiment of the disclosure.

FIG. 8 is a view illustrating the secondary cyclone illustrated in FIG. 7 from another side according to an embodiment of the disclosure.

FIG. 9 is a view illustrating another example of a secondary cyclone of a multi-cyclone dust collector according to an embodiment of the disclosure.

Referring to FIGS. 7 and 8 , the plurality of flow guides 70 may be provided to correspond to at least two of the inlet holes 30 and protrude from an outer surface of the outlet pipe 25 a, thereby minimizing airflow interference between the adjacent inlet holes 30.

As described above, because the three inlet holes 30 are provided at the upper end of the outer circumferential surface of the body 21 of the secondary cyclone 20′, the plurality of flow guides 70 may be provided at a position higher than the lower end of the outlet pipe 25 a to correspond thereto, thereby guiding air introduced into each of the three inlet holes 30.

That is, when air is introduced in the tangential direction into the secondary cyclone 20′ through the plurality of inlet holes 30, the flow guide 70 may guide air introduced into each of the inlet holes 30 to move into the outlet pipe 25 a through the lower end of the outlet pipe 25 a. To this end, the flow guide 70 may be formed to extend toward the lower end of the outlet pipe 25 a.

Each of the plurality of flow guides 70 may be provided between the adjacent inlet holes 30. The flow guide 70 may be provided at a center between the adjacent inlet holes 30.

The plurality of flow guides 70 may be formed as three to correspond to the three inlet holes 30.

Each of the plurality of flow guides 70 may include a guide surface 71, a blocking surface 72 and a cover surface 73. The guide surface 71, the blocking surface 72 and the cover surface 73 may be integrally formed.

The guide surface 71 may be provided to guide air introduced into one of the inlet holes 30. To this end, the guide surface 71 may be formed to extend downward from one end thereof to the other end and to be away from the corresponding inlet hole 30 toward the other end from one end. The flow guide 70 may guide air to move to the lower end of the outlet pipe.

The guide surface 71 may be provided to face the opening 35 of the inflow duct of the secondary cyclone 20′ so that the air introduced in the tangential direction of the secondary cyclone 20′ may be more efficiently guided.

Referring to FIGS. 7 and 8 , the guide surface 71 may have a spiral shape along a circumference of the outlet pipe 25 a. Unlike this, referring to FIG. 9 , a guide surface 71 c may be provided to be inclined with respect to the tangential direction of the secondary cyclone 20′.

The blocking surface 72 may extend in a direction parallel to an extending direction of the outlet pipe 25 a from one end thereof to the other end. That is, the blocking surface 72 may be formed in a direction perpendicular to the tangential direction of the secondary cyclone 20′ from one end thereof to the other end.

The other end of the guide surface 71 and the other end of the blocking surface 72 may be in contact with each other, and the cover surface 73 may cover a space between the guide surface 71 and the blocking surface 72. The flow guide 70 may have entirely a triangular shape.

More specifically, the plurality of flow guides 70 may include a first flow guide 70′, a second flow guide 70″, and a third flow guide (not shown). The first flow guide 70′ may be disposed between a first inlet hole 30′ and a second inlet hole 30″, and the second flow guide 70″ may be disposed between the second inlet hole 30″ and a third inlet hole (not shown).

In this case, referring to FIG. 7 , air introduced into the first inlet hole 30′ may be guided along a guide surface 71′ of the first flow guide 70′. As the guide surface 71′ is formed in a spiral shape, air may flow helically.

Referring to FIG. 8 , the air introduced into the second inlet hole 30″ cannot move in a direction of directing to the first inlet hole 30′ by a blocking surface 72′ of the first flow guide 70′, and may be guided along a guide surface 71″ of the second flow guide 70″.

As such, the plurality of flow guides 70 may guide the air introduced from the corresponding inlet holes 30, respectively, and block the flow of air introduced into the other inlet holes other than the corresponding inlet holes through the blocking surfaces 72, so that the air introduced into each of the inlet holes 30 may effectively move toward the lower end of the outlet pipe 25 a along the corresponding flow guide 70, and thus a decrease in flow loss caused by mixing of air introduced from the inlet holes 30 may be prevented.

Hereinafter, a vacuum cleaner having the multi-cyclone dust collector according to an embodiment of the disclosure as described above will be described.

First, a case in which the multi-cyclone dust collector according to another embodiment of the disclosure is applied to a cordless stick cleaner will be described.

FIG. 10 is a view showing a cordless stick cleaner equipped with a multi-cyclone dust collector according to an embodiment of the disclosure.

FIG. 11 is a partial cross-sectional view illustrating the multi-cyclone dust collector installed in the cordless stick cleaner in FIG. 10 according to an embodiment of the disclosure.

Referring to FIGS. 10 and 11 , the cordless stick vacuum cleaner 100 according to an embodiment of the disclosure may include a main body 110, the multi-cyclone dust collector 1, and the extension pipe 160.

The main body 110 may include a suction motor 120 provided to generate a suction force, a handle 130 provided to grip the cordless stick vacuum cleaner 100, a battery 140 provided to supply power to the suction motor 120, and a connection part 150 provided to allow the extension pipe 160 to be connected. On one side of the suction motor 120, a mounting part 121 to which the base 50 of the multi-cyclone dust collector 1 is mounted is provided. Therefore, the air from which waste and dust are removed while passing through the multi-cyclone dust collector 1 passes through the suction motor 120 and is discharged to the outside of the cordless stick vacuum cleaner 100.

The handle 130 is installed at an upper end of the cordless stick vacuum cleaner 100, and is provided such that a user may operate the cordless stick vacuum cleaner 100 by gripping with a hand. A switch (not shown) capable of turning on/off a power source of the cordless stick vacuum cleaner 100 may be provided on the handle 130.

The battery 140 may be a rechargeable battery capable of being charged using an external power source. One end 151 of the connection part 150 is formed such that the extension pipe 160 may be attached thereto or detached therefrom, and the other end 152 is formed to communicate with the inlet port 11 b of the primary cyclone separator 10 of the multi-cyclone dust collector 1. Between the one end 151 and the other end 152 of the connection part 150, a connection passage 153 through which air containing waste sucked from the outside may pass is provided. Therefore, when the extension pipe 160 is installed at the one end 151 of the connection part 150, external air is introduced into the multi-cyclone dust collector 1 through the extension pipe 160 and the connection passage 153.

One end of the extension pipe 160 is formed to be connected to the connection part 150 of the main body 110, and the suction nozzle 170 moving along a surface to be cleaned to suck waste from the surface to be cleaned may be provided at the other end thereof.

When the power source of the cordless stick vacuum cleaner 100 is turned on, the suction motor 120 rotates to generate a suction force. When the suction force is generated, waste-containing air containing waste and dust on the surface to be cleaned is drawn into the extension pipe 160 through the suction nozzle 170.

The waste-containing air introduced into the extension pipe 160 is drawn into the inlet port 11 b of the multi-cyclone dust collector 1 through the connection part 150 of the main body 110.

The waste-containing air drawn into the inlet port 11 b of the multi-cyclone dust collector 1 is swirled in the primary cyclone separator 10. While the waste-containing air is swirled in the primary cyclone separator 10, the waste is separated by the centrifugal force and collected at the bottom 11 a of the housing 11.

The air from which the waste is separated is introduced into the secondary cyclone 20′ provided in the intermediate chamber 17 through the porous member 13 provided on the intermediate wall 12. In this case, the air is introduced into the secondary cyclone 20′ through the plurality of inlet holes 30 provided on each of the secondary cyclones 20′.

While the air introduced through the plurality of inlet holes 30 is swirled inside the secondary cyclone 20′, fine dust is separated by the centrifugal force and falls along the body of the secondary cyclone 20′. The fine dust separated from the secondary cyclone 20′ is collected into the dust collection chamber 40 through the dust outlet.

As the fine dust is separated, the cleaned air is discharged to the base 50 through the plurality of outlet holes 25 of the secondary cyclone 20′. Because the base 50 is connected to the suction motor 120, the air discharged to the base 50 is discharged to the outside of the cordless stick vacuum cleaner 100 through the suction motor 120.

While the disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. 

What is claimed is:
 1. A multi-cyclone dust collector comprising: a primary cyclone separator configured to separate waste primarily from introduced waste-containing air; and a secondary cyclone separator installed inside the primary cyclone separator, the secondary cyclone separator configured to separate dust from air discharged from the primary cyclone separator, wherein the secondary cyclone separator comprises: a secondary cyclone provided with at least two inlet holes through which air is introduced and an outlet hole through which the introduced air is discharged, and an upper cover provided to cover an upper end of the secondary cyclone and comprising an outlet pipe inserted into the outlet hole to discharge the air, and wherein the upper cover further comprises a plurality of flow guides disposed between adjacent inlet holes to minimize airflow interference between the adjacent inlet holes and provided on an outer surface of the outlet pipe to correspond to the at least two inlet holes.
 2. The multi-cyclone dust collector according to claim 1, wherein the at least two inlet holes are provided at an upper end of an outer circumferential surface of a body of the secondary cyclone to protrude outward from the body, and wherein the plurality of flow guides is provided at positions higher than a lower end of the outlet pipe to correspond to the at least two inlet holes.
 3. The multi-cyclone dust collector according to claim 2, wherein each of the plurality of flow guides comprises a guide surface extending toward the lower end of the outlet pipe to guide air introduced into each of the at least two inlet holes to be moved to the lower end of the outlet pipe.
 4. The multi-cyclone dust collector according to claim 1, wherein the at least two inlet holes are formed in a tangential direction with respect to an outer circumferential surface of each of a plurality of secondary cyclones, and wherein one of the plurality of flow guides comprises a guide surface provided to guide air introduced into one of the at least two inlet holes.
 5. The multi-cyclone dust collector according to claim 4, wherein each of the at least two inlet holes comprises: an opening formed on each of bodies of the plurality of secondary cyclones, and an inlet duct formed to surround the opening to allow air to flow in a tangential direction with respect to an outer circumferential surface of a body, and wherein the guide surface is provided to face the opening of the corresponding inlet hole.
 6. The multi-cyclone dust collector according to claim 5, wherein the guide surface extends downward from one end thereof to the other end, and wherein the guide surface is formed to be away from the corresponding inlet hole from the one end toward the other end.
 7. The multi-cyclone dust collector according to claim 6, wherein the guide surface has a spiral shape along a circumference of the outlet pipe.
 8. The multi-cyclone dust collector according to claim 6, wherein the guide surface is provided to be inclined with respect to the tangential direction.
 9. The multi-cyclone dust collector according to claim 6, wherein the one of the plurality of flow guides comprises a blocking surface provided on a side opposite to the guide surface facing one inlet hole to block air introduced from an inlet hole adjacent to the one inlet hole from being moved toward the one inlet hole.
 10. The multi-cyclone dust collector according to claim 9, wherein the blocking surface extends from one end thereof to the other end in a direction parallel to an extending direction of the outlet pipe.
 11. The multi-cyclone dust collector according to claim 10, wherein the other end of the guide surface and the other end of the blocking surface are in contact with each other.
 12. The multi-cyclone dust collector according to claim 11, wherein the one of the plurality of flow guides further comprises a cover surface provided to cover a space between the guide surface and the blocking surface, and wherein the guide surface, the blocking surface and the cover surface are integrally formed.
 13. The multi-cyclone dust collector according to claim 1, wherein a plurality of secondary cyclones is provided, and wherein the upper cover is provided to cover upper portions of the plurality of secondary cyclones and comprising a plurality of outlet pipes corresponding to the plurality of secondary cyclones.
 14. The multi-cyclone dust collector according to claim 13, wherein the plurality of secondary cyclones comprises a central cyclone provided to correspond to a center of the upper cover and eight peripheral cyclones provided to correspond to a circumference of the upper cover, and wherein a first cyclone has four inlet holes and each of the plurality of secondary cyclones has three inlet holes.
 15. A vacuum cleaner comprising: a suction nozzle; a multi-cyclone dust collector connected to the suction nozzle; and a suction motor connected to the multi-cyclone dust collector, the suction motor configured to generate a suction force, wherein the multi-cyclone dust collector comprises: a primary cyclone separator provided to separate waste primarily from introduced waste-containing air, and a secondary cyclone separator installed inside the primary cyclone separator to separate dust from air discharged from the primary cyclone separator, wherein the secondary cyclone separator comprises: a secondary cyclone provided with at least two inlet holes through which air is introduced and an outlet hole through which the introduced air is discharged, and an upper cover provided to cover an upper end of the secondary cyclone and comprising an outlet pipe inserted into the outlet hole to discharge the air, and wherein the upper cover further comprises a plurality of flow guides disposed between adjacent inlet holes to minimize airflow interference between the adjacent inlet holes and provided on an outer surface of the outlet pipe to correspond to the at least two inlet holes. 